Dominik Schaniel, Theo Woike, Bernard Delley, Colette Boskovic and Hans-Ueli Güdel
Photogeneration of metastable side-on N₂ linkage isomers in [Ru(NH₃)₅N₂]Cl₂, [Ru(NH₃)₅N₂]Br₂ and [Os(NH₃)₅N₂]Cl₂
Phys. Chem. Chem. Phys. 10, 5531-5538 (2008)                 

Abstract: Photogeneration of side-on N₂ linkage isomers in [Ru(NH₃)₅N₂]²⁺ and [Os(NH₃)₅N₂]²⁺ is achieved by irradiation with l = 325 nm of powder samples at T = 80 K and detected by the downshift of the n(N–N) vibration and by the heat release at elevated temperature due to the back switching of the side-on configuration to the ground state. The concentration of the transferred molecules is evaluated by the decrease of the area of the n(N–N) or 2n(N–N) vibrational bands. All characteristic changes between the linear Ru–N–N and side-on configuration are predicted by DFT calculations: the structure of the anion, shifts of the vibrations, electronic excitation energy, energetic position and sequence of the electronic orbitals, the potentials of the ground and relaxed metastable state with the activation energy, saddle points and energetic position of the minimum.